Wire saws were a british invention for RAF escape and evasion in WW2. I believe they were sewn into the uniform along with concealed button compasses in- buttons. As such, they were meant for cutting through fencing, walls etc of cured timber. You just have to be carefull using them on wet wood. There are surgical bone wire saws from 3M you might try. The saw in a can works about on par with any other saw in dried wood. It is by nature going to be more difficult. But I've managed it. I just go a little slower and clear the kerf periodically.